Process for desulfurizing ores.



G. PUSINA.

PROCESS FOR DESULFURIZING 0113s.

APPLICATION FILED APR. 25,1912.

Patented Mar. 16, 1915 2 SHEETQ-SHEET 1.

' ZRLJ-LJQ MW ATTORNEYE- WITNESSES:

G. FUSINA.

PROCESS FOR DESULFURIZING ORES.

APPLICATION FILED APR. 25,1912.

1 ,131,691 Patented Mar.16,1915.

2 SHEETSSHEET 2.

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F GENOA, ITALY.

'PROCESS FOR DESULFURIZING GEES.

ia son Specification of Letters Patent.

Patented Mar, 165, 19115.,

Application filed Aprii25, 1912. Serial No. 693,183.

- .ra all whom it may concern:

Be it known that T, GIOVANNI FUs1NA,-en-

: gineer, a subject of the-King of Italy, residmgat Genoa, Italy, have invented a useful Process for Desulfurizing ()res, of which the following is a specification.

This invention relates to a process for desulfurizing and reducing sulfurous ores such as pyrites, copper pyrites, galenite, zincblende, or the like, or a mixture of the same.

The present invention is essentially distinguishedfrom processes now inuse by the fact that a mixture of air and steam at low pressure is suckedthrough the ore in one direction and thereafterthe mixture is sucked .throughthe ore in the opposite direction,

these reversals being continued until such time as the ore is completely ."desulf'urized. By .this process the desulfurization and reduction of sulfurous ores is practicallycomplete.

In the accompanying drawingsare shown, by way of example, apparatus by which the process may be carried into reflect.

In these drawings: Figure 1 shows an elevation of two furnaces for use in the desulfurization of sulfurous ores, one with continuous air current and the other fitted with reversing device. Fig. 2 is a plan thereof. Fig. 3 is a cross-section of a shaft furnace for desulfurization and reduction of composite sulfurous ores, pyrites, copper pyrites, galenite, zincblende, even if intermixed. F ig. 4: is a plan view of the furnace shown in Fig. 3.

- In the various figures same numbers indicate likeparts.

0n a frame 1 are arranged three parallel endless chains 2, 3, 4:. These chains carry the grates 6 which are held between the links of the side chains. At one end of the frame, as shown, is located the hopper 5 which contains the ore to be treated and discharges same onto the continuously moving grates 6. There is provided ;a reverberatory furnace 7 for igniting or firing the ore, and preferably above this furnace is arranged-an apparatus for supplyingsteam at low pressure. The upper part of the frame is surrounded by a water-trough 9 and attheend opposite to the charging hopper there is a member 10 normally projectin above the lower surface of the grates, w ich acts to lift thegrates from the chains, raising their submerged portions out of the trough and.

causing the latter with its contents to be dropped into a water tank 11 arranged alongside the end of the frame as illustrated. Along the furnace there are three steelplates suction funnels or cones 12, 13, 14: which form an air-tight fitting either with the upper or the lower side of the grate. These funnels are connected by means of steel-plate tubes 15 with a steel-plate general tube leading to thesuction fan. The desulfurization of ores is carried out as follows The chains run at a uniform speed of approximately 10 inches per minute. At the rear of the hopper the grates are arranged upon the .chains to be gripped between the side chain links so as to be conveyed thereby, with their flanged part submerged in the two side troughs, as shown. on passing below the hopper they are charged with ore, which is ignited by the hearth flame; the combustion is strengthened by air and steam being drawn in by the first funnel placed below the grate and connected with a suction fan. This funnel from the hearth flame forward, is approximately 16 feet in length. In this place the burning ore will become incandescent and semi-fluid, and at the end of the 16% feet mentioned the fire will be brought into contact with the grate, whilethe upper layer, beginning to cool, will become darkened. Behind this funnel there is a second arranged above the grate and the ore, and connected like the first with a suction fan. By such an arrangement the ore finedto the lower layers, rises again; and

the reverse .takesplace again when the ore ablaze is brought under the influence of the third funnel, which is placed as the first under the grates; after this the desulfurization is complete and the ore together with the grates is dropped into the water tank.

Before it is fed on to the furnace the ore is reduced to a suitable degree of fineness, and thoroughly mixed up with deoxi'dizing materials, as customary, the mixture containing from 6 to 8% of water at the desulfnrization stage; The desulfurized and concentrated ore is takenout of the water tank and the empty grates are rearranged in place, sprinkled with lime water and their holes cleaned. Arranging everything as shown on the annexed drawing the furnaces output will reach 60 tons of desulfurized and concentrated ore per 24. hcurs, to-

gether with a considerable amount of sul fate of zinc according to the percentage of said metal in the ore to be treated.

The furnace shown in Figs. 3 and 4 is made up of two main parts; one a masonry structure 17 of a square shape outside and round shape inside, the other being the coneshaped steel-plate cover 18. The masonry work rests upon an inclined and impermeable floor; there are in the lower part four openings 19, 20, 21, 22, two, one opposite the other, for the firing and the other two, opposite each other, for the draft. 23 is the grate which is well supported and is formed either of punched steel-plates or iron bars. There are in the masonry work four inspection openings, 24, 25, 26, 27, and in its upper part the masonry work ends in a circular water channel 28. Into this channel the cone-shaped cover which is fitted with eight ports and terminates in a plate tube for the furnace draft dips.

.The charging of the furnace is carried out as follows :-The cover is lifted, and the inside walls and the grate are sprinkled over with lime water, then there is strewn on thegrate a thin layer of limestone pebbles and upon this is arranged the ore in layers. Between the several layers a small amountv of fuel is strewn, which is only intended to keep the several layers of ore apart and to facilitate the emptying of the furnace when the smelting is completed. The ore is finely ground and. thoroughly mixed, so that the various particles are brought. into close contact with deoxidizing material, the relative proportions depending upon the nature of the ore; this acts as a flux in the further treatment of the ore in the blast furnace; it is also suitably moistened, that is there contains from 6 to 8% ofwater. Then the air-tight cover is lowered.

When the furnace is charged, it is fired by means of wood arranged under the grate well. The ore will begin burning after a few minutes and the firing can be quickened by regulating the draft through the tube 29 placed at the upper end of the cover, which is connected with a fan, so that the smoke and gases are discharged to a chimney placed somewhat apart from the furnace. Through the inspection ports, in the power part of the furnace as well as in the cover, the gradual firing of the ore can be watched and the draft ad usted by means of a valve.

. When zinciferous ores are treated steam jets from a special generator are turned on, the steam being drawn in together with the air admitted through the four lower furnace ports. The process is carried on until the whole mass of the ore is ignited and the lower layers begin to become dark owing to cooling. The current is thus reversed, the ore becoming again incandescent and semifluid and a fresh desulfurization taking place; the reversing is repeated as long as there is sulfur unburnt. The cover is then again raised and the mass is slowly sprinkled with Water to assist in the cooling and in the formation of sulfate of zinc, the solution of which filters on to the impermeable furnace bottom, and through suitable openings to a tank. After cooling the furnace is discharged and the ore taken to the lixiviation vats for the recovery of the sulfate of zinc, while the insoluble portion, which contains lead partly converted into pure metal, is carried directly to the blast furnace. negligible percentage-ofzinc, after desulfurization, as explained above, While they are still incandescent, they may be subjected to a further reduction to convert them to the metallic state, by employing reducing gases obtained by the use of sulfurous and sulfuric acids. In this case the furnace walls should be lined with fireproof material.

Having now particularly described and ascertained the nature of my said invention and in what manner the same is to be performed, I declare that what I claim is 1. A process for desulfurizing ores which consists in passing a quantity of air through the material in one direction and then passing a quantity of air and steam through said material in the. opposite direction.

2. A process for desulfurizing ores which consists in passing air through a mass of ore in one direction and then passing air throu h said mass in the reverse direction.

3. g process for desulfurizing ores which consists in igniting the surface of a mass of ore to a state of incandescence, sucking air through the mass to cause other parts of the mass to become incandescent, sucking air after a determined period of time through the mass in the opposite direction, and thereafter reversing the direction of flow of the mixture at determined intervals so as to cause the incandescent action continuously to change from the upper to the lower layer of ore andv vice versa.

When the ores treated have but a I 4. A process for desulfurizing ores of the to a mass of ore to be treated, progressively moving the mass on a conveyer during such time as the desulfurization continues, lgnit- 6. A process of desulfurizing ores which consists in passing a quantity of air transversely through the mass to be treated, and

in reversing the direction of flow of the air 15 after a determined interval, substantially as described.

In testimony whereof I aflix my signature in presence of two Witnesses.

GIOVANNI FUSINA.

Witnesses P10 Rmo'rom, ANGELO BORAGINO. 

